1. Field of the Invention
The present invention relates generally to building construction. Particularly, the present invention relates to a modular building assembly. More particularly, the present invention relates to a monolithic post and beam reinforced concrete structure using a system of permanent forms.
2. Description of the Prior Art
A common form of modern building construction is steel frame construction. Steel frame construction is relatively expensive due to the expense of the structural steel and the skilled labor involved. A less expensive method of construction is that of reinforced concrete construction. All reinforced building construction requires forms to mold the concrete into the different structural shapes required to carry the building loads. The forms create the voids where steel reinforcing rods are placed followed by filling with concrete in its fluid state, which is poured creating the structural components such as columns, walls, beams, floors, and roof slabs.
There are two distinct ways of building reinforced concrete structures with numerous combinations of both. There is conventional form making at the job site. In such construction, concrete forms are erected at the site, steel reinforcement rods placed in the forms, and concrete poured into the forms to create walls, load bearing columns, and floors of reinforced concrete. Upon curing of the concrete, interior and exterior facing panels are then secured to the outside surfaces, especially walls and floors, resulting in a reinforced concrete structure. This method still requires extensive amounts of on-site labor, which can be quite expensive when compared to factory labor.
A second way to build reinforced concrete structures is to prefabricate the components in a factory. Fabrication of construction components can be carried out at lower cost in a factory setting. This type of construction method is known as precast concrete structural components. This is accomplished by the manufacture of all or part of a structure at an off-site factory and then transporting the components to the site for assembly. The following prior art addresses various systems and methods for building structures utilizing pre-cast concrete structures.
U.S. Pat. No. 1,469,955 (1923, Reilly) discloses using a plurality of wall blocks having recesses in their ends designed to form spaces when the blocks are set together for receiving concrete to form a plurality of columns. Some of the wall blocks have outer walls projected above the inner walls to form a seat on the inner wall for receiving a floor comprised of a plurality of tiles, slabs and a concrete floor interlocked with the slabs.
U.S. Pat. No. 1,757,077 (1930, Eiserloh) discloses building construction that includes a series of duplicate wall sections fashioned with staggered vertically extending openings. End edges of the tiles abut and middle portions therebetween are recessed. The opposed recesses define a duct or well and corner sections are L-shaped. A trough is permanently set along the tops of the wall sections. The troughs are provided with a series of definitely spaced apertures. Preformed beams are shaped to fit in the apertures. The beams support flooring and extend across parallel walls with their ends occupying a pair of aligned apertures.
U.S. Pat. No. 3,712,008 (1973, Georgiev et al.) discloses a modular building construction system in which prefabricated modules are supported on a separate framework, the individual members of the framework also being modular and prefabricated. The framework also defines vertical and horizontal passages required for utilities, corridors, elevators, etc. The prefabricated modules are generally constructed off the site and assembled together on the job during erection of the building.
U.S. Pat. No. 3,300,943 (1967, Owens) discloses a tilt-up building system for producing a monolithic construction. Prefabricated reinforced wall panels are tilted-up or raised to vertical positions of support upon vertical spacer members positioned upon a continuous footing at longitudinally spaced intervals. There are gaps between the panels and footings where reinforcing rods are positioned and secured. The gaps are then formed in to define voids and concrete is poured in to fill the void forming a reinforced concrete belt between the panels and footings. The forms are then removed from the panels and footings.
U.S. Pat. No. 4,081,935 (1978, Wise) discloses a building structure in which precast columns and beam and deck members are used. Upper columns are supported in spaced apart relationship to lower columns by pairs of rods extending from each column and clamped together. Topping concrete is poured to lock the members together into a unitary structure.
U.S. Pat. No. 4,127,971 (1978 Rojo, Jr.) discloses a building constructed of precast L-shaped concrete units. The precast L-shaped concrete units are obtained by utilizing reusable mold forms and casting the units vertically on a wheeled base between separable vertical mold forms. The concrete unit is transported on the wheeled base from between the separated molds to complete the curing. The building is erected on a concrete slab foundation using a plurality of precast concrete units in the form of L-shaped walls. H-beams are placed across the tops of the walls and filled with concrete to serve as a support and anchoring means for precast concrete roof slabs.
U.S. Pat. No. 4,343,125 (1982 Shubow) discloses a building block module and method of construction. Reinforced concrete building block modules are assembled into load bearing walls. The modules are configured as hollow rectangles having beveled corners with reinforcing rods extending through the side of the rectangle into the beveled spaces. The spaces are filled with concrete to form solid columns of reinforced concrete construction through which continuous reinforcing extends. The floors can be either poured or precast floor sections. The modules are erected into vertical walls that are integrated into a wall-floor system, whereby the walls support the building floors.
A disadvantage of the prior art regarding precast concrete structural components is that the structural systems depend on field point connections (e.g., welded steel plates, anchor bolts, post-tensioned cables, etc.). Building stresses concentrate at these field point connections, requiring redundancy in their design to avoid failure of the whole system in the event one connection fails. The design redundancy increases the use of materials and requires highly skilled labor, supervision and costly quality controls at the building site. The increased weight and size of these components requires costly transportation and expensive hoisting equipment. Another problem with these systems is sealing and waterproofing their joints, which is very costly and has to be replaced and maintained every 5 to 10 years increasing greatly the cost of the building.
A disadvantage of the prior art regarding conventional form making at the job site is that the construction methods are time consuming, require intensive skilled labor, exposure to weather conditions that affect scheduling and quality control of the forms, limited dimensional accuracy and wasteful in material consumption. Also, once the forms are stripped, the unfinished reinforced concrete surfaces require plastering or the use of other finishes like brick, tiles, stone, etc., unless expensive liners are used.
Therefore, what is needed is a reinforced concrete structure that provides for reductions in both the volume of concrete used and in the overall weight of the building. What is further needed is a reinforced concrete structure that provides for reductions in both steel reinforcement materials and in the labor for steel reinforcement. What is also needed is a reinforced concrete structure that provides reductions in both shoring and footing sizes. What is yet further needed is a reinforced concrete structure that provides reductions in forming (creating concrete forms), form removal and overall construction time. What is still further needed is a system that incurs a reduced transportation cost due to a reduction in weight of the precast concrete components. What is also needed is a reinforced concrete structure that provides for a reduction in capital costs, which are tied up in temporary forms, their installation, removal, care and storage. Finally, what is needed is a building of increased quality.